If you want to avoid paint patterns then use a marking applicator.. this way you will have control over what markings you want to put on the horse.. You can then choose from rabicano, Rn+ or RnRn or white.. if you dont want any paint markings

A marking randomizer doesnt give you any choice.. you could use it and end up with overo, tobiano, tovero and then some.. best to use applicator.